If steam engine cycles were implemented would the average Joe refill water every day?
 

If water steam cycles were implemented for higher engine efficiency would the average Joe remember to refill water every day?

If sea water could be used in steam systems in cars driven on arid lands could then cars actually prevent or reverse desertification?

Water vapor cycles can be either

Six stroke engine
Six-stroke engine - Wikipedia, the free encyclopedia

Blowing water in the exhaust to boost turbo power recovery
or just Steam turbines
Steam turbine - Wikipedia, the free encyclopedia

External combustion engines
External combustion engine - Wikipedia, the free encyclopedia
Steam engine - Wikipedia, the free encyclopedia

Other advanced steam technologies
Advanced steam technology - Wikipedia, the free encyclopedia

I wouldn't see why not.

No it wont. That much water vapor would be a fart in the wind. I have been to places in africa and the middle east where its very humid all day and night. Just because its desart doesn't mean its dry.

That wont work. Turbochargers are heat engines.
You use that heat to do work. It can drive a turbine or boil water.
Boiling the water is work, if you boil water before the turbine so much sensible heat will be lost to latent heating of the water the exhaust stream wont have a high enough temperature to expreance much of any temperature drop when it goes accrost the turbine, there for wont be able to do any work.
Turbochargers already boost fuel economy by up to 20% on diesels.

Turbochargers are /pressure/ engines, not heat engines. If the water evaporates while crossing the face of the turbine, the steam expansion rate creates a higher pressure differential across its face, thus increasing the power by which it can be driven. The heat is completely circumstantial to this process.

As I vaguelly recall water expands about 1600-times in volume between its liquid and vapor states (assuming equal temperature and external pressure)...explaining why something that weighs 8.3 lbs/gal in liquid form becomes "lighter-than-air" in vapor form.

Both you and Old Tele man are correct.
 

The turbocharger, like all turbines, are mass flow engines. Heat and pressure do work to move a mass of working fluid through the turbine producing power. Think of the turbines in a hydroelectric dam.

I think you just proved his point. A hydroelectric dam uses pressure from the reservoir to run the turbine. From what I know, most lakes are not hundreds of degrees, showing why pressure is the important factor.

EDIT: I didn't see the 'title' of your post, that's exactly what you did! :turtle:
___________________________
OP: I don't think people would remember to add water everyday. We might remember to do it, but the average Joe would probably not. Think about how many people forget to change their oil or coolant or trans fluid. Now they have to do it every day?!?! Unfortunately, I just don't have faith...

[QUOTE=Christ;413214]Turbochargers are /pressure/ engines, not heat engines. If the water evaporates while crossing the face of the turbine, the steam expansion rate creates a higher pressure differential across its face, thus increasing the power by which it can be driven. The heat is completely circumstantial to this [QUOTE]

If this worked why isnt it in use on large turbodiesel power generators, ship engines or gas turbine power plants?

I know some engineers I can pitch this idea to. I already know their first reaction will be to laugh at me.

Not to mention the idea of having liquid water droplets in contact with the turbine is a bad idea. Causing drag, erosion things things you dont want.

Question would be what do people do when they run out of NOS or meth? You know, for a chemical intercooler not getting high. :eek:

I pitched this idea to my engineer, after a long awkwardly long peroid of laughter, a string of obscenities which cant be posted her his only responce I can repeat on here is "some one failed thermo".

The idea that heat is circumstantial to a turbochargers turbine is laughable to say the very least.
If it isnt why are all turbine calculations done with temperture differential?

heat is circumstantial to pressure. The temp differential calculation gives you an idea of how much pressure is generated using the temp diff across the face of the turbine.

Turbines are not heat engines, they are pressure differential engines. Your 'engineer' is mixing up principles.

If you don't believe me, put a vacuum cleaner nozzle on the exhaust out port of a turbo, or just blow compressed air through the turbine inlet.

BUT PRESSURE AND TEMP DIFFERENTIAL BLAH BLAH BLAH

No. Just no. If you wanna try it again, blow some compressed propane through it. You'll not only freeze the turbine blades from the complete lack of heat energy in the propane as it vaporizes, but it will spin and create discernible boost if piped into a closed environment.

Heat is not the determining factor in a turbocharger's performance. Pressure and flow are. The heat is circumstantial, but not necessary.

BTW - I've seen some very low compression competition engines feed compressed air to the turbine to spool it while starting up. Typically 2 stroke engines where the OE supercharger has been replaced with a large frame turbocharger.

Lets also keep in mind that not all turbines operate using heat as a source of energy, and thus, since all turbines operate on fundamentally the same principle, turbines, by default, can /not/ be necessarily heat-driven engines as a primary function.

So, I reiterate - pressure differential, not temperature differential, is the primary factor.

If steam engine cycles were implemented would the average Joe refill water every day?
 

Some assumes that steam engines need too be refilled with water. LOL

[QUOTE=oil pan 4;413251][QUOTE=Christ;413214]Turbochargers are /pressure/ engines, not heat engines. If the water evaporates while crossing the face of the turbine, the steam expansion rate creates a higher pressure differential across its face, thus increasing the power by which it can be driven. The heat is completely circumstantial to this Some notes:
Gas turbine power plants and ship turbine engines already get this effect without adding water. The use compound turbines to wring all the heat out of the turbine. This is an old trick that dates back to steam turbines.
Large turbodiesel engines *can* do this. I think Audi (or maybe BMW) does this in research cars. It was originally done in military bombers:
Turbo-compound engine - Wikipedia, the free encyclopedia
Wright R-3350 Duplex-Cyclone - Wikipedia, the free encyclopedia
After dealing with the complexity of these engines, the engineers switched to turboprops and (and jets) and never looked back. I don't think piston-turbine-compound engines have any advantages over normal turbines (I'll explain the reason it at least justifies the research for the Germans a bit later).

As far as adding water to a heat engine: a simple experiment will help here (EPA willing). Do an A-B-A experiment changing from E0 to E10/E15/E85. Since there is almost certainly a degree of water in the alcohol mix, you will be adding water to your car's engine. If you notice a gain over the actual engergy containted in the gas, it was likely the water (unless your car can detect the E85 and crank up the CR), like the reverse. I know from at least one other time this was suggested, at least one forumite had a strong agrument that adding water *reduced* the pressure. It certainly removes a lot of heat (good old phase change) and the pressure of the resulting water vapor + air was indeed lower (our trusty forumite had checked the expansion coeffecients).

The real reason you would add steam (especially for automotive turbo-compounding apps) is that gas turbines operate in the 10k-100k rpm region and steam engines operate in the 100-10k regions. I wouldn't be surprised if the Germans didn't need any gearing (but I think running the steam at half the engine speed might be ideal). Steam makes it possible to directly couple the two engines without the huge gearboxes needed for turbines, and likewise is missing the exotic material requirements for ultra-high rpms. I'm still not convinced you couldn't mount a turbine (really, half a turbocharger) to a hybrid/range extender and drive a generator with it.

[edit: just noticed a thread with this link in it. Apparently adding water *does* work, just that you will be adding gallons/mile]
http://ecomodder.com/forum/180860-post10.html
detailed explanation about heating steam (never mentions the effects of pressure due to steam expansion. You really need to include that).
http://ecomodder.com/forum/showthrea...y-21437-3.html

If these turbochargers are not heat engines then why are rear mounted turbos typically 5% to 10% less efficient and more laggy?

I can't believe you're still on this... honestly.

Rear mounted turbos are more laggy and lose efficiency because latent heat in the exhaust dissipates as it travels through the pipe, reducing the overall pressure across the face of the turbine.

I know that's exactly what answer you were looking for, and you're going to pick one word out of that answer to try to prove your point, but trust me, it doesn't. The fundamental working principle behind turbine engines is pressure. How you get that pressure makes zero difference, as long as it's there.

Both of you are right to some point and wrong in another.
 

The crux is the work derived from the mass flow through the turbine. Pressure and temperature provide the impetus to move your working fluid through the turbine which then extracts work from the fluid mass. Higher temperature and pressure in a gas turbine inlet result in potentially greater mass flow into the turbine. A drop in exit pressure and temperature is a direct result of the loss in energy of the working fluid which was transferred to the turbine. The fluid ( or gas as it may ) is assumed constant. Note that lighter (less dense gas or fluid ) will produce less power at a given pressure and temperature. Hydrogen gas will produce less power than steam. Some lab work has been done in the past using vaporized mercury to take advantage of the high specific mass density.

So which is it? Mass flow or pressure drop?

If its not a heat engine then why isnt some one injecting water into the exhaust stream and seeing major gains in turbine performance, proving aerospace and mechanical engineers all wrong.
If a turbocharger is not a heat engine then why did an aerospace engineer I know go to great lengths to insulate the piping on his diesel for the specific reason of getting as much heat as possible to the turbine inlet?

Maybe you are right and engineers are all just stupid. It could easily be proven with the water injected steam turbine thingy. Seems easy enough to prove, take a diesel put water injection on the exhaust, flip the switch on off on off results in test complete. I would do it but I know it would be a waste of time, first of all it wont work and then when it fails you will claim it failed because my bias.
A true believer needs to see it fail first hand, back to back, over and over.

Mass flow.
 

Of course temperature and pressure directly affect the flow through the turbine. They are also linked together. Increasing temperature usually results in increased pressure and the ability to move the mass of the gas more rapidly providing more potential for work per unit time ( power ).

This why it makes sense to have a free flowing exhaust to reduce pressure robbing bends. And insulating the exhaust preserves as much of the heat ( temperature ) to do work on the turbine. Again, the temperature of a gas is a measure of how much each molecule is vibrating and moving and impacting a barrier resulting in pressure.

And sometimes injecting water into the exhaust stream can yield greater mass flow and power out of a turbo but under very specific caveats.

I think you just put this to bed, right here (again).

A turbo is a pressure based engine. Heat is, in essence, a form of pressure, in that the molecules react more creating a larger pressure on the surroundings (e.g. turbine). Calling it a heat engine is only a part of the puzzle, it's not the wrong answer, it's just that it's only a part of the right one.

http://www.youtube.com/watch?v=b7t2VjZ1DvY

You can have static pressure.
 

The same way you can have a static torque reading and produce no power until that torque results in movement over a period of time, so is the need to produce motion from the turbine. However, if the mass moving through the turbo charger turbine is too small the power produced by the turbo will also be small even though you may have a high pressure/temperature reading at the inlet reiterating the need for free flowing exhaust systems.

In the case of a turbo charger, pressure and temperature are a good measure of the mass flow through the turbo charger since one can assume the exhaust gas is constant for this calculation.

OilPan4 -

Water will also drive a turbine... you need sufficient flow and pressure. Never heard of a hydro dam?

Your experiment will not work not because it tests a principle you believe to be faulty, but because the test itself is faulty. The water will only contain as much kinetic energy as is supplied via a pump, of which only about 54% can be extracted, in connection with Betz's law. (Which is generally applied to wind, but is also recognized as a principle of fluid dynamics in general. Unless the water is turned into steam as it crosses the face of the turbine, being used to extract latent heat from the turbine itself as it passes, no 'extra energy is generated and thus, only the amount of energy put into the flow and pressure of the water, up to Betz limit, can be extracted. The result is a net loss.

As per the rest of your comment, your attitude is a waste of time and you're starting to come across as a stubborn child with the thinly veiled insulting tone of your commentary and your constant appeals to authority. This will be my last reply to you on this subject.

Rusty, there isn't much temperature drop across the turbine stage, the mass flow is from heat/expansion in the combustion chamber, that is where the turbine gets its energy (like the mass flow below):

https://www.youtube.com/watch?v=hzVSycvnFmM

I take that as no one is actually going to try this?

Alright I lied a little bit... your friend heat wrapped his down pipe because keeping the heat in the pipe before the turbine increases the pressure difference across the turbine housing.

The problem with your thought that a turbine is inherently a heat engine isn't that it doesn't function with heat, its just that heat is not the root principle of its operation, which is what I'm trying to explain this whole time. A pressure differential of any kind, with any fluid medium, will drive the turbine. In the case of the exhaust driven turbocharger specifically, you can see that the turbocharger presents a restriction to flow, initiating a post-combustion pressure stage. The pipe between the engine and turbine is a heat sink, and we already known that pressure increases in a closed space as temperature is increased. Its a common fault, and I don't blame you for thinking this way at all.

Wrapping that pipe iaulates it against later heat loss, which keeps a maximum pressure differential between the input and output of the turbine allowing it to operate with greater efficiency. The maths refer to DeltaP here when calculating the output power of the turbine shaft, asking for the pressure differential as an input, and this can be derived with some certainty using a temperature input if one wishes to analyze a freeze frame of the potential output under a given set of circumstances. In order to fully analyze a turbocharger system, you would need the inputs of mass flow and engine exhaust flow, as well as downpipe volume and turbine sizing, pitch, etc.. a much more complicate set of maths that is such less commonly used where simplicity is a factor.

What the latter would tell you is, under at set of conditions in which a turbine might be found to operate, what efficiency and output it wud have. This is part of how flow maps re created for specific designs of turbochargers.

I think I covered everything now...

Sorry fr typos... Tablet and shaky hands

Those I know who run 30 psi of boost in their e85 conversions wrap the exhaust, snail, etc to reduce under hood heat. If it does help performance its soo little its unmeasurable.

Diesels dont have extreme under hood temperatures like gas engines and diesels are not as sensitive to higher temperatures like gas engines.

I dont think this way, this is how engineers think, they showed me. I didnt make this up.

Yeah, most of the heat in a diesel engine today is from the egr water cooler that uses the coolant. I know many diesel owners who had trucks that ran warm and went with an egr delete and instantly they started to run on the cool side.

This is correct.
 

Preserving the energy to the turbo is the point of the exercise.

Yes, but the turbine in a turbo isn't a peltier junction or a stirling engine. Preserving the exhaust heat is basic PV=NRT stuff, decrease T and P goes down. The IC is a gas generator, and waste heat is entropy's way of saying screw y'all (unless it is cold outside, then maybe you have a use for it).

I agree.
 

What is the point of your discussion?

Lost heat before the turbo results in less pressure which results in less mass moved through the turbine.

Point? I dunno, you tell me.

Anyway I think it is worth distinguishing between gas and diesels too. Turbo's seem to be an efficiency penalty on gas engines, while an efficiency boost on diesels.

lower peak bsfc for spark normally aspirated (page 874, fig 15-38)
lower peak bsfc for diesel turbo (page 876, fig 15-40) (plus much better power/weight at improved bsfc)


http://www.rmcet.com/lib/E-Books/Mec...ndamentals.pdf

The original post was for steam engines . . .
 

. . . which was extended to the idea of a partial steam implementation in the exhaust driven turbo charger.

You are now extending the discussion to another area. Maybe a new thread is in order.

But, your reference is interesting in that many people assume that the increased efficiency gained by a diesel with a turbo charger applied can also be found by applying a turbo charger to a gasoline engine ignoring the differences in combustion operation. That is not the case.

Thank you for the link by the way. Heywood is a classic.